Friction-surface and method of forming same.



P. H. FRANZ.

FRICTION SURFACE AND METHOD 0F FORMING SAME.

APPLICATIO ED nec 21 1914 l l 55,054. Patented Sept. l28, 19l5.

' fn uen fof' fr any: u

UNITED TtrEs rafranvr oFFioE.

PAUL H. FRANZ, OF DOLGEVILLE, NEW YORK, ASSIGNOR TO DANIEL GREEN FELTSHOE COMPANY, F BOSTON, MASSACHUSETTS, A CORPORATION Oil-MASSACHUSETTS.

Specification of Letters Patent.

l Patented Sept. 28, 1915.

Application led December 21, 1914. Serial No. 878,328.`

v To all 'whom t may concern:

' hardening same.

Be it known that I, PAUL H. FRANZ, a citizen of the United States, and aresident of Dolgeville, in the county of Herkimer and State of New York,have invented certain new and useful Improvements in Friction Surfacesand Methods of Forming Same, of which the following is a specification.

In the formation Aof linings for brake bands, -fiat or cone-shapedclutch rings or like frictional surfaces, it is essential for theadvantageous operation of such mechanisms that the frictional surfaceshave a perfect t when brought into operative contact, that is to say,their operating surfaces, when engaged, should contact with substantialequal pressure over the entire area of the respective faces, and not inisolated portions, as so often occurs where linings of leather or othersimilar materialsare employed.

My invention relates, therefore, to the formation of friction surfaceswhich may be used in clutches, brakes and the like, and consists in soforming and compressing a cloth fabric, such as an all-wool felt, to theshape required for such clutch or brake lining, and thereafterimpregnating same with a solution of suitable resinous substancesv whichshall become viscous `underfrictional heat and which shall not onlyincrease the positive frictional grip of the surfaces when brought intocontact, but also the durability of the lining of such friction surfacesthrough the perfect fit obtainable 'by the use of my improved method informing and After the felt has been impregnated with the solution ashereinafter described, the vfacing is compressed and allowed to dry andharden, when it will retain -its shape and general contour and will vbefound in use to have greater durability and effectiveness than otherclutch and brake linings now in common use. For example, I have employedthe following method in making my improved frictional surface as thefacing of a cone clutch I-It is very important in my process that thefelt shall be shrunk to reduce same in size, and hardened to the shapeand form desired. In doing this, I first place a suitably cut piece offelt on the male member of a clutch-g such piece may be cut too large orit may be cut too small; after it is placed on the male part, the feltfacing is' thoroughly soaked in hot lparts are thereafter securedtogether. rl`he water and the male part of the clutch is then forcedinto the female part and the two felt facing is then dried by theapplication of heat, the felt shrinking in all directions and conformingto the contour of the clutch through the contraction or curling up ofthe individual fibers of the matted wool com-v prising the felt fabric.My reason for thus shrinking the felt facing is to get a tight fit uponthe male part of the clutch, and my reason for forcing it into thefemale part of the clutch is to cause it to be tightly secured to themale part, and there let it shrink to form in contact with the femalepart of the clutch surface thereby to obtain a perfect fitting frictionsurface which shall be symmetrical throughout the entire facing and ofsubstantial uniform texture, the fibers of the felt having contracted inthe shrinking. When this facing or lining is thoroughly shrunk anddried, I remove same from the clutch and apply thereto the followingsolution :,-I first take thirty (30) pounds of shellac and mix it withfive (5) gallons of wood alcohol, and heat 'saine to the neighborhood of150 degrees Fahrenheit; I then mix twelve (12) pounds of powdered rosinwith three (3) gallons of turpentine and heat same to the neighborhoodof 95 degrees Fahrenheit. After the above combinations are Yheated totheir respective temperatures as hereinbefore set forth, I pour theminto a suitable receptacle and miX them together, constantly stirringthe mixture during their union; and I then gently boil same for aboutten minutes. The solution is now ready to be applied to the facing orlining, or it can be further reduced with alcohol, depending on thepurpose for clutch. I have found that the first method of application isthe most preferable, where a positive and immediate action in the clutchamount of slipping between the surfaces is necessary and desirable. Thesolution can be applied to any friction fabric, at any time when thesame gives evidence of slipping, either by wear, or by unavoidable oillubrication from the machinery in which such friction surface may b eused.

After the facing or lining has had the solution hereinbefore describedapplied thereto, it is again fastened to the male clutch member andforced into the female part of the clutch which has the effect ofspreading the preparation through and over the felt facing or lining,and allowed to dry. After it is completely dried this frictional surfacewill be found to be suiiiciently hard to hold its shape, and can beremoved and thereafter attached to any clutch of the same dimensions andcontour as the one upon which it was shrunk to form and impregnated withthe solution as hereinbefore set forth.

In making linings for brakes it is advisable to stretch the feltthoroughly before applying the solution, and, in making frictionaldisks, theV felt may be cut to the form of such disk, and thereaftersaturated with such preparation and then pressed under heat to therequired thickness.

The proportions of the substances in the impregnating solution used,which I have hereinbefore stated, may be Varied within considerablelimits, depending entirely on the result desired from the frictionalsurface to be employed in any mechanism, as it is obvious that otherproportions can be employed according to special conditions or as to theobject to be attained. If a very positive frictional engagement isdesired, a correspondingly thick solution of shellac, properly heated topenetrate in all the fibers or interstices of the felt, must beemployed, whereas the thinner the solution of shellac, the less will bethe frictional power of the facing or lining.

The friction caused by the engaging of the felt facing of the malemember with the female memben of my clutch causes the shellac to becomesticky between the clutclr faces. The rosin in such prepared felt facesis also warmed and becomes sticky for the same reason as the shellac. Itherefore put the rosin in the solution because it will combine with theoil which is likely to leak into the clutch during the operation of themachine to which the clutch maybe attached, and the oil and rosincombined, under the heat of friction, also makes a sticky frictionalsurface which will cause a perfect clutch or brake, even if the feltfacing is entirely covered with oil.

By the use of the term impregnating the felt fabric it is not intendedto limit the scope of this invention to immersing and saturating thefabric in the resinous solu tion, but such term includes the applicationof the solution to the. fabric`by use of a brush or any other suitablemeans.

The accompanying drawings illustrate one form of apparatus for carryingout my improved method informing the4 friction surfaces for a coneclutch embodying my invention.

Figure 1 is a perspective View of a felt disk 5 cut ,to form Ythe facingof a cone clutch; F ig. 2 is a similar view showing the disk 5 mountedon the cone-shaped male member 6 of the clutch; Fig. 3 is a view partlyin cross section showing Ythe disk 5 compressed between the male member6 and the female member 7 of the clutch; and Fig. 4 is a perspectivevview of the friction surface finally formed and ready to be used asthefacing of a cone clutch. Y.

I claim as my invention 1. The method of forming friction surfaces froma felt fabric, which consists in shrinking the felt fabric to form, thenimpregnating the shrunk felt fabric with a solution of resinoussubstances, and finally drying V under pressure the impregnated fabric.

2. The method of forming friction surfaces frrom a felt fabric, whichconsists in shrinking the felt fabric to form, then impregnating theshrunk felt fabric with a heated solution of resinous substances, andfinally drying under pressure the impregnated fabric.

3. The method of forming friction surfaces from a felt fabric, whichconsists in shrinking the felt fabric to form, then impregnating theshrunk felt fabric with a solution of resinous substances comprisingshellac and rosin, and finally drying under pressure the impregnatedfabric.

4. 'Ihe method of forming friction surfaces from a feltl fabric, whichconsists in shrinking the felt fabric to form, then impregnating theshrunk felt fabric with a heated solution of resinous substancescomprising shellac and rosin, and finally drying under pressure theimpregnated fabric.

5. The method of forming friction surfaces from a felt fabric, whichconsists in shrinking the felt fabric to form, then impregnating theshrunk felt fabric with a solution of resinous substances composed ofshellac cut with alcohol and rosin cut with turpentine, and finallydrying under pressure the impregnated fabric.

' 6. The method of forming friction surfaces from a felt fabric, whichconsists in shrinking the felt fabric to form, then impregnating theshrunk felt fabric with a heated solution of resinous substancescomposed, of shellac cut with alcohol and rosin cut with turpentine, andfinally drying. under pressure the impregnated fabric.

7. A friction surface composed of a felt having the fibers andinterstices of the fabric "impregnated with a solution of resinoussubstances, becomin viscous under friction.

5 8. A friction 4sur ace composed of a felt fabric, shrunk andcompressed to form, and

having thebers and interstices of the fabi fairic, shrunk and compressedto form, andv ric impregnated with a solution of shellac cut withalcohol and resin cut` with turpentine, becoming viscous under friction.

' PAUL H. FRANZ.

Witnesses:

FRANGIS L. MUNsoN, WmLIAM C. KINUM.

